<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
<style>
#myImg {
    border-radius: 5px;
    cursor: pointer;
    transition: 0.3s;
}

#myImg:hover {opacity: 0.7;}

/* The Modal (background) */
.modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    padding-top: 100px; /* Location of the box */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.9); /* Black w/ opacity */
}

/* Modal Content (image) */
.modal-content {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
}

/* Caption of Modal Image */
#caption {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
    text-align: center;
    color: #ccc;
    padding: 10px 0;
    height: 150px;
}

/* Add Animation */
.modal-content, #caption {    
    -webkit-animation-name: zoom;
    -webkit-animation-duration: 0.6s;
    animation-name: zoom;
    animation-duration: 0.6s;
}

@-webkit-keyframes zoom {
    from {-webkit-transform: scale(0)} 
    to {-webkit-transform: scale(1)}
}

@keyframes zoom {
    from {transform: scale(0.1)} 
    to {transform: scale(1)}
}

/* The Close Button */
.close {
    position: absolute;
    top: 15px;
    right: 35px;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    transition: 0.3s;
}

.close:hover,
.close:focus {
    color: #bbb;
    text-decoration: none;
    cursor: pointer;
}

/* 100% Image Width on Smaller Screens */
@media only screen and (max-width: 700px){
    .modal-content {
        width: 100%;
    }
}
</style>
</head>
<body>

<h2>图片模态框</h2>
<p>本实例演示了如何结合 CSS 和 JavaScript 来一起渲染图片。</p><p>
首先，我们使用 CSS 来创建 modal 窗口 (对话框), 默认是隐藏的。<p>
<p>然后，我们使用 JavaScript 来显示模态窗口，当我们点击图片时，图片会在弹出的窗口中显示：</p>
<img id="myImg" src="http://www.runoob.com/wp-content/uploads/2016/04/img_lights.jpg" alt="Northern Lights, Norway" width="300" height="200">

<!-- The Modal -->
<div id="myModal" class="modal">
  <span class="close">×</span>
  <img class="modal-content" id="img01">
  <div id="caption"></div>
</div>

<script>
// 获取模态窗口
var modal = document.getElementById('myModal');

// 获取图片模态框，alt 属性作为图片弹出中文本描述
var img = document.getElementById('myImg');
var modalImg = document.getElementById("img01");
var captionText = document.getElementById("caption");
img.onclick = function(){
    modal.style.display = "block";
    modalImg.src = this.src;
    modalImg.alt = this.alt;
    captionText.innerHTML = this.alt;
}

// 获取 <span> 元素，设置关闭模态框按钮
var span = document.getElementsByClassName("close")[0];

// 点击 <span> 元素上的 (x), 关闭模态框
span.onclick = function() { 
    modal.style.display = "none";
}
</script>

</body>
</html>